Wells are commonly used to access regions below the earth's surface and to acquire materials from these regions. For instance, wells are commonly used to locate and extract hydrocarbons from underground locations. The construction of wells typically includes drilling a wellbore and constructing a pipe structure, often called “casing,” within the wellbore. Upon completion, the casing provides access to the underground locations and allows for the transport of materials to the surface.
Before, during, and after construction of a well, a variety of tools may be used to monitor various properties of the downhole environment. For example, underground acoustic logging systems may be used to inspect a casing, the surrounding cement support structure, and/or the surrounding subterranean formations. These systems may be positioned independently within a wellbore, or may be placed on a drill string and positioned within the wellbore in conjunction with other downhole equipment. Acoustic logging systems typically include a transmitter that directs acoustic energy towards the periphery of the wellbore, and a receiver that detects acoustic energy reflected back to the logging system (e.g., acoustic energy reflected from the casing and/or from the subterranean regions beyond the wellbore. Based on the measured reflections, the monitoring system provides information regarding the casing and its surrounding environment.
Like reference symbols in the various drawings indicate like elements.